hagan



March 24, 1964 A. w. HAGAN 3,126,143

CARTON Original Filed Oct. 7, 1957 4 Sheets-Sheet 2 46 46a /6 46a /6 46a#6 46m 74 79 22' 8o 29 8/ 77 65 83 1 88 46c I I l 1 US j 5 INVENIORALBERT W. HA GAN BY Q W W ATTORNEY5 March 24, 1964 A. w. HAGAN 3,126,143

CARTON Original Filed Oct. 7, 1957 4 Sheets-Sheet 3 mvzm'on A LBERT W.HAen/v rrows March 24, 1964 A. w. HAGAN 7 3,126,143

CARTON 4 Sheets-Sheet 4 Original Filed Oct. 7,- 1957 AL5ER7 W HAGANATTORNEYS United States Patent 3,126,143 CARTQN Albert W. Hagan,Stratford, Conn, assignor to Roy S. Sanford & Company, Oxford, Conn, apartnership Original application Get. 7, 1957, Ser. No. 688,576, newPatent No. 3,43%358, dated .lune 26, 1962. Divided and this appiicationFeb. 9, 1962, Ser. No. 179,833 6 Claims. (l. 22937) This inventionrelates to cartons of paper-board, fiberboard and sheet materialssuitable for the formation of cartons having foldable end flaps, andparticularly to a novel sift-proof construction for a carton of theabove type. The terms paper-board and fiberboard are usedinterchangeably in the specification and claims.

One of the objects of the present invention is to provide a novelpaper-board carton blank which is readily adapted for quick andefiicient sealing, the construction being such that complete sealing ofall pin holes and cracks is achieved, thus providing a container havingend portions which are completely sift-proof when the carton is utilizedfor powdered materials such as flour, for example.

Another object of the invention is the provision of a cartonconstruction so constituted as to eliminate the need for inner bags oroverwraps commonly utilized for the purpose of preventing sifting of thepowdered contents.

A further object of the invention is to provide a siftproof carton ofpolygonal cross section formed from a single piece of low cost materialsuch as paper-board.

Still another object of the invention is to provide a onepiece cartonblank scored to permit folding in such a manner as to permit efiicientand positive sealing of the end flaps under relatively low pressure.

A still further object of the invention is to provide a sift-proofcarton of paper-board or the like, so constructed as to effectively sealthe corners against leakage of the contents without relying on adhesiveto seal the pin holes which commonly are found in cartons of thisgeneral type.

in the manufacture of paper-board cartons of this general type, it isnot too difiicult to properly seal one end of the container, since whenthe first end is sealed, the end flaps can be held together under highpressure, a mandrel being inserted in the container to support the flapson one side, and a pressure plate being placed against the flaps on theoutside in order to properly seal the fiaps. Difficulty is experienced,however, in sealing the other end of the container after it has beenfilled, and it is a further and important obiect of the invention toovercome this difiiculty, and to provide a con- :l'llCilOll wherein theend of the carton which is sealed after fiiling of the carton can bemade sift-proof with very little pressure being applied to the foldedend flaps which close the end of the carton.

A still further object of the invention is to provide a new and novelcorner construction for a carton.

Yet another object of the invention is to provide a corner constructionfor a paper-board carton which will stand rough handling without causingthe corners of the carton to leak.

Other objects and novel features of the invention will appear more fullyhereinafter from the following detailed description when taken inconnection with the accompanying drawings, wherein several embodimentsof the invention are illustrated. It is to be expressly understood,however, that the drawings are utilized for purposes of illustrationonly, and are not to be taken as a definition of the limits of theinvention, reference being had for this purpose to the appended claims.

in the drawings, wherein similar reference characters refer to similarparts throughout the several views;

FIG. 1 is a view of a blank adapted to be formed into a carton of theabove type;

FIG. 2 is a view of a modified form of carton blank;

PEG. 3 is a fragmentary view of another modified form of carton blank;

FIG. 4 is a fragmentary view of a further modification of the cartonblank;

FIG. 5 is a view of still another modified form of carton blank;

BIG. 6 is a perspective view showing one step in the formation of onecorner of a carton from the blank shown in FIG. 1;

FIG. 7 is a perspective view showing another step in the formation ofthe corner of the carton of FIG. 6;

FIG. 8 is a perspective view of a further step in the formation of thecarton corner of FIG. 6;

FIG. 9 shows a step in the formation of one corner of a carton from theblank of FIG. 5;

FIG. 10 shows another step in the formation of the corner of FIG. 9;

FIG. 11 shows another step in the formation of the corner of FIG. 9;

BEG. 12 is a perspective view of a portion of a completed carton formedfrom the blank shown in FIG. 1;

FIG. 13 is a perspective view of a portion of a completed carton formedfrom the blank shown in FIG. 2;

FIG. 14 is a perspective view of a portion of a completed carton formedfrom the blank shown in FIG. 3 and HQ. 15 is a perspective view of amandrel and pressure pad for forming the end of a carton.

The present invention is particularly directed to a carton constructionwhich is economical in the use of paper-board, which can be readilyfabricated, and which does not require complicated folding mechanism inorder to produce a sift-proof carton. In this connection, it should benoted that the corners of a conventional carton of the type utilized forthe packaging of flour, cake mixes or the like, is a very rigidstructure, and that in the event the carton is dropped on the floor andhits on a corner of the carton, the carton is generally dam aged at thecorners to such an extent as to cause serious sitting of the contents.In the event an overwrap is used, this is generally ruptured at thecorner, and since the carton itself is not sift-proof at the corner,leakage occurs. It is well known that such cartons receive rather roughhandling in chain grocery stores and the like, and Eonfiequently theloss due to damaged cartons is quite The carton of the present inventionhas a corner construction which overcomes these difficulties, since thecorner is not rigid in the sense that the corners of a conventionalcarton are rigid, and while crushing of the corner due to dropping thecartons may change the appearance of the corner by crushing some of thepaperboard, it does not cause leakage or sifting at the corners. Cartonsof this construction have been dropped repeatedly from heights of two orthree feet without causing sifting of the contents, the contentsutilized in these tests being very finely ground flour. Explaining thematter in another way, it is pointed out that the rigid corner of theconventional carton buckles when dropped on the floor, thus rupturingthe paper-board, while the carton of the present invention may beconsidered to have the corners already buckled slightly, so that furtherdisplacement can occur without rupturing the paper-board.

Referring more particularly to FIG. 1, the present invention isillustrated therein as including a container blank 4, shown forconvenience in a vertical position, having main wall panels 5, 6, 7, and8, and a glue flap panel 9 adapted to be adhesively secured to the edgeportion of the wall panel 5, the inner surface of the blank being shown.The wall panels and 6 are connected by a narrow vertical panel 10, wallpanels 6 and 7 are connected by a narrow vertical panel 11, wall panels7 and S are connected by a narrow vertical panel 12, and the wall panel8 is connected to the glue flap 9 by means of a narrow vertical panel13. The edges of these narrow panels are defined as shown by verticalscore lines or fold lines 14. The narrow vertical panels 10, 11, 12 and13 are very narrow relative to the width of the main sidewall panels,and consequently, when the carton is folded into a tubular shape withthe glue flap 9 connected to the panel 5, the resulting carton tube isessentially rectangular in cross section, and there is a narrow verticalpanel at each corner of the carton tube having a surface preferablydisposed at an angle of 135 to the panels on either side thereof.

Since both ends of the carton blank. in this figure are shown assubstantially identical, only the upper end will be referred to indetail in the description immediately following. A score line or foldline 15 extends across the carton at the upper end at substantiallyright angles to the vertical score lines 14, and foldable end flaps 16,17, 18 and 19 are connected respectively to sidewall panels 5, 6, 7 and8 along this score line. In addition a small end flap or extended glueflap 20 may be utilized connected with the glue flap 9 and a portion ofthe narrow vertical panel 13 along the score line 15. The end flaps 16,17, 1S and 19 are separated from each other as by means of cut lines 21,22 and 23, the flap 19 being separated from the small flap 29 by asimilar cut line 24. The term cut lines refers to the separation of theend flaps, either by single cut lines or by the removal of paper-boardbetween the flaps. It will be noted that the above referred to cut linesare preferably substantially in alignment with the vertical center linesof the panels 10, 11, 12 and 13 respectively, that they are preferablybut not necessarily terminated slightly above the horizontal score line15. Adhesive coatings 25 of any suitable type are applied to the largeend flaps 17 and 19 as shown, and although the adhesive is shown ascovering the entire inner surface of these flaps, it will be understood,as will be more fully explained hereinafter, that other adhesivepatterns may be utilized without departing from the principles of the invention. In addition, a narrow strip of adhesive is applied along theedge of the vertical wall panel 5 in order to secure this panel to theouter surface of the glue flap 9. In like manner, a narrow strip ofadhesive 28 is applied to the left edge of the end flap 16 in order tosecure the latter to the outside surface of the panel 20 when the blankis folded into tubular form.

At the bottom end of the carton blank, the construction is, asheretofore stated, the same as that at the upper end of the blank, andincludes end flaps 29, 30, 31, 32 and 33 all arranged in the same manneras the end flaps at the upper end of the blank, these lower end flapsbeing separated as by means of cut lines 34, 35, 36 and 37, alsoarranged in the same manner as the cut lines 21, 22, 23 and 24 at theother end of the blank. These end flaps also include adhesive coatings38, 39 and 40, arranged in a manner corresponding to the adhesivecoatings 28, 25 and 26 at the upper end of the blank.

In setting up the carton, the blank is preferably folded around amandrel 41, shown in elementary form in FIG. 15 of the drawings, thismandrel having relieved corner portions 42 adapted to conform to thenarrow vertical panels on the blank when the latter is folded, and aflat top portion 43 against which the end flaps are folded to close theend of the carton. A pressure block 44 is provided, and when the endflaps on the first end to be closed have been folded with the adhesivecoatings therebetween, the pressure block is moved downward by suitablemeans, not shown, in order to press the flaps together. During thisclosing operation, the blank is first wrapped around the mandrel, andthe left side of the panel 5 is brought into overlapping relationshipwith the glue flap 9 on the outer surface thereof, the end flap 16likewise being brought into overlapping relationship with the outersurface of the panel 20. At the other end of the blank, the left side ofthe end flap 29 is brought into overlapping relationship with the outersurface of the small end panel 33. The overlapping portions areadhesively secured together, the result being a tube which assumes thecrosssectional shape of the finished carton. Thereupon, the upper endpanels 16 and 18 are folded downward at right angles to the adjacentwall panels 5 and 7 against the upper end 43 of the mandrel, andthereafter, the panels 19 and 17 are folded inward in the order namedover the outer surfaces of the panels 16 and 18, being secured theretoand to each other by the adhesive coatings 25 and 26. The pressure pad44 is now moved down ward in order to press the flaps together insealing relationship. As will be more fully explained hereinafter, whenthe panels are folded as above described, small nibs of paper-board areleft protruding outwardly at the corners, and these nibs, thearrangement of which will be more fully described hereinafter, serve toeffectively seal the corners and prevent any sifting of powderedmaterial from the carton. It is pointed out again, in this connection,that very little pressure is required to form the end of the carton, thepressure pad 44 acting against the folded end flaps merely serving toinsure uniform contact therebetween.

Following the above operations, the carton is inverted, the lower endnow becoming the top of the carton. The carton is then filled with thedesired material, whereupon the end flaps 29 and 31 are folded inwardlyat right angles to their adjacent wall panels, following which panels 32and 30 are folded inwardly in overlapping relationship in the ordernamed, although it is to be understood that the order of folding ofthese flaps as well as the flaps 17 and 19 at the other end of thecontainer can be reversed if desired, and it is to be further noted thatif desired, the large end flaps can be folded first in overlappingrelationship, and the small end flaps can be folded over thereafter. Theconstruction described is the preferred construction, however, since itresults in a better appearance and an unbroken surface on the end of thecarton.

The folding of the end flaps at one corner of the carton is shown inenlarged perspective views of FIGS. 6, 7 and 8. It will be noted thatwhen the blank is folded in tubular form with the end flaps stillunfolded, the lower ends of the cut lines between the end flaps join theapex of a more or less triangular portion 45 of the carton material, thebottom of the triangular portion being defined by the horizontal scoreline 15. If desired, as shown in FIG. 4, the other two sides of thistriangular portion may be defined by score lines 46 and 46a. These scorelines are not necessary in all cases, but in some types of paperboard,they assist in the proper folding of the end fiaps when the end is beingclosed. In FIG. 6, the corner of the carton is shown before any of theend flaps have been folded and the triangular portion 45 can be readilyseen. As the next step in the end closing operation, see FIG. 7, one ofthe end flaps may be folded downward at right angles to the adjacentwall panel, and it will be seen that the triangular portion 45- tends tofold along the sides of the triangle tending partially to fill thecorner of the container. In the next step, the other fiap may be foldedinwardly on top of the first flap, the end flaps forming an outstandingnib 4611, see 8. Since the inner surface of one panel is coated withadhesive, it adheres firmly to the other panel. It will be apparent fromthe foregoing that the nib is in the form of what might be termed abellows fold, and that the paper is crowded together in this fold insuch a manner as to effectively seal the corner regardless of whether ornot the adhesive extends fully into the corner, the same actionoccurring at the other corners.

Assuming that the flaps just folded are on the last end of the box to beclosed, it will be apparent that the lower portion of the carton withits closed bottom forms a fairly rigid member when subjected to verticalcompression loads, and that a light force exerted on the top of thecarton against the folded end flaps is sullicient to form a flat end onthe carton. This may be done by placing a weight on the folded end flapsor by means of a suitable machine, not shown, and it is only necessaryto apply sufilcient pressure to engage the end flaps with each other andto flatten the nibs 46b downward substantially into the plane of theremaining portion of the top end of the carton. It has been found thatvery little pressure is required to accomplish this. From the foregoing,it will be noted that in the event a pin hole is formed at the corner itmust be positioned at the apex of the outstanding nib, and since theconstruction is such that paper-board at the location of this pin holeis crowded very tightly together due to the nature of the fold and dueto the arrangement of the narrow corner panels 12, the pin hole iscompletely sealed and will not be subsequently opened up in such a wayas to leak even though it may be crushed by dropping the carton on ahard surface. It should also be noted, referring to FIGS. l5, that theend fiap 16 is cut away on an angle at point 46s in such a manner thatthe angular edge portion thus formed conforms, when the blank is foldedinto tubular form, with one edge of the adjacent triangular portion 4 5,so that when the left edge of the panel 16 is adhesively joined to theouter surface of the panel 29, the panels 115 and 20 form one small endflap which can be folded in without interference. Thus, the glue flappresents no difficulty in the forming of the corner adjacent thereto.

Due to the arrangement of the panels 1%, 11, 1.2 and 13 in the cartonconstruction just described, the completed carton, instead of being-very rigid, is quite flexible, and when handled, acts more like a bagthan like a rigid carton. In the case of cartons utilized for flour andsimilar products, this is sometimes desired by the manufacturer, sincewhen the end of the carton is opened to dispense the flour, the sides ofthe carton can be readily squeezed together to assist in properlycontrolling the dispensing of the hour from the carton.

In other cases, however, a more rigid type of carton is desired, andthis is readily accomplished by a construction such as that shown in theblank of FIG. 2. This carton also includes main wall panels 5, 6, and 7and d, and glue flap 9 as well as upper end flaps l6, r17, 18 and 19 andextended glue flap 26, in the same manner as shown in :FIG. 1. Also, thepanels 16 and 17, 17 and 18, 18 land 19, and 19 and Zt'l are separatedby cut lines 21, 22, 23 and 24, these lines terminating a short distanceabove the horizontal score line 15 which defines the boundary betweenthe side Wall panels and the end flaps. The construction of this cartonis the same at both ends, and consequently only the upper half will bedescribed in detail. The upper end portions of the wall panels 5, 6, 7,8 and the glue flap are connected adjacent their upper ends by narrowvertical panels 47, 4-8, 49 and 5%). These are located relative to theadjacent wall panels in substantially the same manner as the narrowvertical panels shown in FIG. 1, and the cut lines between the upper endflaps are substantially in line with the center lines of these narrowpanels. The lower ends of the panels are preferably defined by diagonalscore lines or fold lines 51 and 52, and these score lines merge intosingle score lines 53 dividing the adjacent wall panels and beingsubstantially in alignment with the vertical center lines of panels 47,4-8, 49 and St The same construction may be utilized at the lower end ofthe blank, the lower end being provided with end flaps 29, 30, 31, 32and extended glue flap 33, separated respectively by cut lines 34, 35,36 and 3'7 terminating a short distance below the horizontal score line33a. The lower end portions of the panels 5, 6, 7, 8 and 9 are connectedby narrow vertid cal panels 54, '55, 56, and 57, the upper end of thesepanels being defined by score lines 58 and 59which merge at their upperends with the lower ends of the score lines 53.

When the main side panels are folded at right angles to each other toform a carton tube of substantially rectangular cross sect-ion, theyfold about the vertical score lines 53, and the side wall panelsadjacent the score line 15 are connected by the narrow panels 47, 4-8,49 and 50 in the same manner that the side wall panels in FIG. 1 areconnected throughout their length by the narrow vertical panels 10, 11,12 and 13. Thus, the corner construction of this carton is identicalwith that of the carton shown in FIG. 1, but in view of the fact thatthe carton sidewall panels fold about the vertical score lines 53, thecentral portion of the carton between the upper and lower ends of thescore lines is rigid in the same manner as a conventional carton, andthis rigidity is enhanced by the formation between the folded sidewallpanels of triangular portions 60- which merge at their lower apices withthe score lines 53, and at their upper ends 'with the small verticalpanels 47, 48, 49 and 5%. These small triangular portions 6d tend tobrace the adjacent sidewalls against relative angular movement,resulting in a very rigid and easily handled carton structure. In thisconnection, it should also be noted that the left edge of the verticalwall panel 5 is so contoured as to conform, when folded into a tube,with the score lines 53, 52 and 5? on the glue flap 9, as well as wit-hthe edges of the short vertical panels 50 and 57. As will be seen inFIG. 13 showing a completed carton formed from the blank of FIG. 2, itwill be apparent that this arrangement results in a very neat andattractive looking form of construction in the region of the glue flap,the junction of the panel 5 with the glue flap being hardly noticed. Asimilar construction is also utilized in the blanks of FIGS. 1, 3 and 4.

A further modification is shown in FIG. 3, the carton blank havingsidewall panels 5, 6, 7 and 8 and glue flap panel 9 as was the case inthe blanks already described. This end of the carton is provided withend flaps 16, 1'7, 1%, 1% and extended glue fiap Ell, separatedrespectively by cut lines 21, 22, 23 and 24, these lines terminating ashort distance above a horizontal score line 15 defining the lower edgesof the end flaps. In this case, the sidewall panels adjacent the centralportion of the carton are arranged to hinge about vertical score lines61, terminating at their upper ends at the junction of angularlydisposed score lines 62, 63, 64-, 65, 66, 67, 68, and 69. These latterscore lines define triangular panels 7d, 71, 72 and 73, the upper endsof these panels being defined by the horizontal score line 15, and thevertical center lines of the panels being substantially in linerespectively with the end flap cut lines 21, 22, 23 and 24. When thecarton is folded to form a tube, the main side panels fold about thevertical score lines 61 to form a carton having a rectangular crosssection in the central portion thereof, while the triangular panelsconverge inwardly from those score lines toward the horizontal scoreline 15, the material above the score line converging slightly outwardlytherefrom toward the lower ends of the cut lines between the end flaps.Here again, the corner construction when the end flaps are folded inoverlapping relationship is substantially identical with that shown inFIG. 1, but the appearance of the finished carton is quite differentfrom that of the carton of FIG. 1, and the carton is also much morerigid to handle. In this case, the left edge of the panel 5 is contouredto conform, when the blank is folded in tubular Shape, with the verticalscore lines s1 and the score line as on the glue flap 9, see FIG. 14. Itwill be understood that the lower end of this carton blank may be formedin the same manner as the upper end as described, or that the lower endof the blank if desired may be formed as SLOWH in FIGS. 2, 4 or 5.

A further modification is illustrated in FIG. 5, showing the upperportion of the carton blank. This blank includes main wall panels 5, 6,7 and 8 and glue flap panel 9, these panels being connected by narrowvertical corner panels 18, 11, 12 and 13 as already described inconnection with FIG. 1. A horizontal score line 15 separates these wallpanels from end flaps 74, 75, 76 and 77, and extended glue flap panel78. These panels are separated respectively by cut lines 79, 80, 81 and82, but it will be noted that these cut lines are arranged differentlyfrom the cut lines shown in FIGS. 1, 2 and 3 insofar as they are relatedto the vertical center lines of the narrow vertical panels 19, 11, 12and 13. By way of example, the cut line 79 is positioned slightly to theleft of and parallel with the vertical center line of the narrowvertical panel 16, and terminates at its lower end in a portion 33curving downward to the right to the center line of the panel 10. Inlike manner, the vertical cut line 81) is at the right of the verticalcenter line of the panel 11 and is curved downward to the left at itslower end at 84 toward the center line. The cut line 81 is disposed inthe same manner as the out line 79, and the cut line 82 is disposed inthe same manner as the cut line 80. Consequently, the panels 75 and 77are wider than the corresponding panels 17 and 39 in FIG. 1, forexample, and when folded inwardly at right angles to the adjacentsidewall panels 6 and 8, the upper corner portions of the end flaps 75,and 77 substantially conform to the outer peripheries of nibs 46b, andwhen adhesively secured together, serve to maintain the nibs in theplane of the carton ends. The folding of the flaps, however, takes placein substantially the same manner as in the other constructionsheretofore described, the triangular portions at the corners above thehorizontal score line 15 folding in a more or less bellows form andforming outwardly extending nibs as heretofore described, see FIGS. 9,and 11. It is to be understood in this connection, that the remainingportion of the carton may be constructed in the manner shown in FIGS. 1,2, 3 or 4 if desired without departing from the spirit of the invention.In this case, it will be noted that the lower portion of the left sideof the end flap 74 is formed at 85 with a contoured edge portion mergingwith the left edge of the panel 5, and adapted to conform to the curvedportion formed on the right side of the upper ends of the blank by thecurved portion at the lower end of the out line 82.

It will also be noted that the left and right edges and the upper edgesof the large flaps '75 and 77 are slightly curved in this embodiment ofthe invention. When the carton is in completed form, the sidewalls ofthe carton at the extreme ends are curved outward very slightly, andthis contouring of the large end flaps is such that when the flaps arefolded, their edges tend to conform more closely with the contour of thesidewall ends along the score line 15. In addition, due to the fact thatthe large end flaps are wider than those shown in the other embodiments,the left and right edges of these end flaps conform more fully with theupper ends of the narrow sidewall panels. Also, the large end flaps attheir outer corners tend to cover the nibs 46!; more fully, and beingadhesively secured thereto, tend to maintain these nibs in a flattercondition than would otherwise be the case. The sift-proof cornerconstruction is essentially the same, however, the paper-board in thesmall triangular portion above the score line folding in substantiallythe same manner as heretofore described in connection with the otherembodiments of the invention.

Upper portions of completed cartons formed from the blanks of FIGS. 1, 2and 3 are shown in perspective in FIGS. 12-14, these views showing thejunction of the opposite edges of the blank at the glue flap, andshowing the outstanding nibs and the corner construction of the carton.

t will be apparent from the foregoing description that a novel cartonconstruction has been provided, so constituted that the blanks are veryeconomical in the use of paperboard, and have a substantiallyrectangular shape when completed, the blanks being of one-piececonstruction and requiring only a minimum amount of adhesive in order tosecure the end flaps together in overlapping relationship. The uniquecorner construction at the junc tion of the sidewalls and theoutstanding nibs at the corner of the carton provide a carton having avery attractive appearance and great customer appeal, and theconstruction of the corners and the nibs at the corners is such thatthey can be repeatedly crushed or distorted in handling withoutdetracting from the sift-proof feature of the carton. The carton canreadily be formed into a tube on a mandrel or otherwise, and the endflaps then sealed either with the aid of pressure in a machine or byhand if so desired, it being particularly pointed out that the last endto be closed can be readily sealed in a sift-proof manner by pressure onthe end of the carton, something which can not be done with theconventional type of carton commonly used. In this connection, it ispointed out that the large fiaps shown in FIG. 1, for example, need notbe fully coated with adhesive, but that the adhesive may be applied asshown at the upper end of FIG. 2. This also applies to FIGS. 3-5. Here,a narrow band of adhesive 86 may be provided along the edge of the flap17, and a similar band of adhesive 87 may be applied along the edgeportion of the end flap 19, this being all that is necessary to insure asatisfactory sealing of the end of the carton. It will be understood,that adhesive will be applied along the left edge of the panel 5 and theleft edges of the end flaps 16 and 29 in a manner similar to that shownin FIG. 1, in order to permit the panel 5 to be bonded to the outersurface of the glue flap 9, and to per mit the end flaps 16 and 29 to bebonded effectively to the outer surfaces of the extended glue flappanels 2% and 33.

The construction is such that various types of adhesive may be utilized,and by way of example, the adhesive may be of the heat sealing varietyprinted on the flat blanks during manufacture, or a solvent type ofadhesive can be printed on the blanks and activated by a suitablesolvent during the sealing operation. If a heat-sealing type of adhesiveis utilized, this can be activated by heat during the erection of thecarton. This carton is also adapted to the use of so-called wet adhesivesuch as is commonly used in carton plants to side seam conventionalcarton blanks, it only being necessary that the adhesive have sufficienttack to hold the flaps together after they have been folded inoverlapping relationship. This type of adhesive is normally lower incost than so-called heat sealing and solvent types of adhesives and canbe used very advantageously in the construction of cartons of this type.

The versatility of the carton construction described will be readilyapparent to those skilled in the art, in view of the fact that thecarton may be constructed in accordance with FIG. 1 to provide a packagewhich has some of the characteristics of a bag in order to permit theuser to readily dispense the contents, while some of the other formsdescribed and illustrated provide for a particularly rigid carton whilestill retaining the advantages of the siftproof corner. The carton formsshown entirely eliminate the necessity for an inner bag or an overwrapfor the purpose of preventing sifting of the contents, and consequentlythis type of carton is much more economical than those which require aninner bag or an overwrap. No special techniques are required in formingthe blank, and it is readily adaptable to production in carton plantsalready equipped for the manufacture of the more conventional typeblanks.

The sealing of the ends can be accomplished entirely by hand if desiredfor small production runs, or the ends can be sealed by simple machinerywhich does not require great force to effect sealing of the end flaps.The sidewalls of the carton are rigid enough to permit the end flaps tobe pressed downward to provide a flat surface at the top end of thecarton by exerting a downward pressure on the outer end flap by means ofa suitable pressure plate which may be operated manually or in asuitable machine, not shown. Since it is only necessary to provideadhesion between the flaps along the outer edges thereof, it will beunderstood that the vertical sidewalls of the carton provide sufiicientrigidity to permit the flaps be sealed together along these edges bysuitable pressure on the top end of the closed carton. In the carton ofordinary construction wherein the corners of the carton comprise threeadjacent walls at right angles to each other and meeting at a point, itis virtually impossible, after filling the carton, to close the upperend flaps and seal them in overlapping relationship without leaving pinholes at corners through which the contents tend to escape. Thisdifficulty is entirely overcome by the present invention. The cartonalso oifers much better protection to the contents as compared with theordinary carton, in view of the fact that there are no pin holes at thecorners through which air or vapor can pass back and forth as the cartonis subjected to various changes in temperature.

Although the cut lines separating the foldable end flaps have beenillustrated as being single cut lines, it is to be understood that theseend flaps may be separated by either single cut lines or by spaced apartcut lines without departing from the spirit of the invention. Inaddition to the above, it is also pointed out that the point or"terminaion of these cut lines adjacent the horizontal score line 15 isnot critical and that the lines if desired may terminate at thehorizontal score line itself without detracting from the efiiciency ofthe corner construction in preventing sitting of the carton contents.The arrange ment shown, however, is the preferred form. It is also notessential to have the terminals of the cut lines located on the centerline of the narrow panels which connected the main sidewall panels, assuch terminals can be at either side of the center line provided theyare positioned between extensions of the score lines which define thesides of the narrow vertical corner connecting panels. The importantthing is to have a portion of each end flap at each side thereofintegral with a portion of the narrow corner panels, thus providing thematerial necessary to provide the bellows type fold at the corner whichproduces the outstanding nib 4612 when the carton flaps are folded. Forconvenience, the carton has been illustrated as having a generallyrectangular cross-sectional form, but the invention is also applicableto other polygonal cartons having more or less than four main sidewallpanels. It is also pointed out, that although the nibs 46b arepreferably pressed down substantially into the plane of the outer endflap on the carton, this is not essential to the sift-proofness of thecarton, and is done primarily for the sake of better appearance. Theconstructions shown in FIG. 2 to FIG. 5 can be used interchangeably onopposite ends or at different corners of a single carton if desired inorder to provide a distinctive appearance to the carton foridentification purposes or otherwise.

This application is a division of my co-pending application Serial No.688,576 filed October 7, 1957, now Patent No. 3,040,958, for Carton.

While several modifications of the invention have been illustrated anddescribed herein with considerable particularity, it will be understoodby those skilled in the art, that various changes and modifications maybe made without departing from the spirit of the invention. Referencewill, therefore, be had to the appended claims for a defininition of thelimits of the invention.

I claim:

1. A sift-proof fiberboard carton of substantially rectangular crosssection including four main sidewall panels with the adjacent panels atright angles to each other, two of the panels being connected by a glueflap, narrow corner panels at least at each end portion of the cartonconnecting three of the sidewall panels and the other sidewall panel andglue flap and angularly disposed thereto, and end flaps at the ends ofeach sidewall panel and the glue flap panel folded at right angles tothe corresponding sidewall panels and glue flap panel and adhesivelysecured together in overlapping relationship, each of said end flapsadjacent the corresponding corners of the carton having adjacent cornerportions integral with the corresponding corner panels, said cornerportions of the end flaps being folded one over the other in overlappingrelationship and forming substantially triangular nibs extendingoutwardly of the plane of the outer surfaces of the corresponding cornerpanels, said three sidewall panels and said one side wall panel and glueflap panel in a portion of the carton intermediate said end portionsbeing directly connected along single fold lines.

2. A fiat blank for a tubular sift-proof carton of genenerallyrectangular cross section, said blank including four flat main verticalsidewall panels, and a vertical glue flap panel at one side of theblank, the adjacent sidewall panels and the outer sidewall panel andglue flap panel at said one side of the blank being connected, at leastat the upper end portion of the blank, by flat narrow vertical cornerpanels along separate spaced apart vertical score lines, foldable endflaps at the upper ends of said sidewall panels and glue flap panelconnected thereto along a common horizontal score line, cut linesseparating the adjacent foldable end flaps, each out line terminating ata point adjacent to but spaced above said horizontal score line, each ofsaid cut lines being substantially in alignment with the vertical centerline of the corresponding flat corner panel, the inner end of each cutline and the ends of the horizontal score line at the upper end of saidcorresponding flat corner panel forming the apices of a small flattriangular panel, each said small triangular panel being integral with apair of adjacent foldable end flaps and with the adjacent fiat cornerpanel, and the other side of said blank, at least at said upper portionthereof, having a vertical edge on the other outer sidewall panel,adapted when the blank is folded to form a tube having the adjacentsidewall panels at right angles to each other, to register with thescore line between the glue flap panel and the adjacent corner panel,and to terminate at the junction of said last named score line and saidcommon score line, an edge on the end flap at the end of said otherouter sidewall panel extending angularly outward and upward from saidjunction and having a length and being at an angle to said commonhorizontal score line such that the lower end of said angularlyextending edge is substantially in register with the junction of saidcommon horizontal score line and the upper end of the score line betweenthe glue fiap and adjacent fiat corner panel and the other end of saidangularly disposed edge is substantially in register with the lower endof the cut line separating the foldable end flaps at the upper ends ofthe glue flap panel and the adjacent sidewall panel, and a vertical edgeon the side of the end flap at the upper end of said other sidewallpanel extending upward from the upper end or" said angularly disposededge and adapted to register through at least a portion of its lengthwith the edge of the foldable flap at the upper end of said glue flapformed by the cut line between said last named flap and the adjacentfoldable end flap, the adjacent sidewall panels and said outer sidewallpanel and glue flap in the region below said upper end portion of theblank being connected along single fold lines substantially in alignmentwith the vertical center lines of the corresponding corner panels, andthe upper ends of said single fold lines and the lower ends of thecorresponding corner panel fold lines defining the corners of smalltriangular panels at the lower ends of the corner panels.

3. A blank for a sift-proof fiberboard carton as set forth in claim 2,wherein said narrow corner panels are defined by upwardly diverging foldlines intersecting said lateral fold line, and the adjacent sidewallpanels and the glue flap panel and said outer sidewall panel below saidcorner panels are directly connected along vertical fold linesintersecting the junction of the lower ends of said fold lines.

4. A blank for a sift-proof fiberboard carton as set forth in claim 1,wherein the blank includes fold lines defining triangular panels at theupper ends of said corner panels, the bases of said triangular panelscoinciding with said horizontal score line, and the other sides of saidtriangular panels being defined by fold lines extend ing from thejunctions of the upper ends of said narrow panel fold lines with thelateral fold line to the lower ends of said out lines.

5. A blank for a sift-proof fiberboard carton as set forth in claim 2,wherein the cut lines separating said end flaps are positioned such thatthe major portion of two alternate end flaps at their right and leftedges extend beyond the vertical center lines of said corner panels, thecut lines having curved portions at their lower ends merging with thecenter lines of the corner panels adjacent said horizontal score line.

6. A blank for a sift-proof fiberboard carton as set forth in claim 2,wherein the outer edge of the end flap at the upper end of the sidewallpanel on the side of the blank opposite to said glue flap panel iscontoured to register, when the blank is folded into tubular form andthe glue flap panel and said one sidewall panel are adhesively joined,with the inner edge of said extended glue flap and with the junction ofsaid lateral fold line and the fold line at the junction of the glueflap panel and the narrow corner panel connecting said glue flap paneland said one sidewall panel.

References Cited in the file of this patent UNITED STATES PATENTS941,356 Byrne Nov. 30, 1909 944,614 Jenkins Dec. 28, 1909 1,146,115Weiss July 13, 1915 1,206,839 Gruenberg Dec 5, 1916 2,050,894 Paige Aug.11, 1936 2,485,235 Graf Oct. 18, 1949 2,596,225 Eaton May 13, 19522,761,611 Benschoter Sept. 4, 1956 2,783,933 Sharts Mar. 5, 19572,830,505 Guyer Apr. 15, 1958 FOREIGN PATENTS 905,479 France Feb. 11,1944

2. A FLAT BLANK FOR A TUBULAR SIFT-PROOF CARTON OF GENENERALLYRECTANGULAR CROSS SECTION, SAID BLANK INCLUDING FOUR FLAT MAIN VERTICALSIDEWALL PANELS, AND A VERTICAL GLUE FLAP PANEL AT ONE SIDE OF THEBLANK, THE ADJACENT SIDEWALL PANELS AND THE OUTER SIDEWALL PANEL ANDGLUE FLAP PANEL AT SAID ONE SIDE OF THE BLANK BEING CONNECTED, AT LEASTAT THE UPPER END PORTION OF THE BLANK, BY FLAT NARROW VERTICAL CORNERPANELS ALONG SEPARATE SPACED APART VERTICAL SCORE LINES, FOLDABLE ENDFLAPS AT THE UPPER ENDS OF SAID SIDEWALL PANELS AND GLUE FLAP PANELCONNECTED THERETO ALONG A COMMON HORIZONTAL SCORE LINE, CUT LINESSEPARATING THE ADJACENT FOLDABLE END FLAPS, EACH CUT LINE TERMINATING ATA POINT ADJACENT TO BUT SPACED ABOVE SAID HORIZONTAL SCORE LINE, EACH OFSAID CUT LINES BEING SUBSTANTIALLY IN ALIGNMENT WITH THE VERTICAL CENTERLINE OF THE CORRESPONDING FLAT CORNER PANEL, THE INNER END OF EACH CUTLINE AND THE ENDS OF THE HORIZONTAL SCORE LINE AT THE UPPER END AND THEENDS OF THE HORIZONTAL SCORE LINE AT THE UPPER END OF SAID CORRESPONDINGFLAT CORNER PANEL FORMING THE APICES OF A SMALL FLAT TRIANGULAR PANEL,EACH SAID SMALL TRIANGULAR PANEL BEING INTEGRAL WITH A PAIR OF ADJACENTFOLDABLE END FLAPS AND WITH THE ADJACENT FLAT CORNER PANEL, AND THEOTHER SIDE OF SAID BLANK, AT LEAST AT SAID UPPER PORTION THEREOF, HAVINGA VERTICAL EDGE ON THE OTHER OUTER SIDEWALL PANEL, ADAPTED WHEN THEBLANK IS FOLDED TO FORM A TUBE HAVING THE ADJACENT SIDEWALL PANELS ATRIGHT ANGLES TO EACH OTHER, TO REGISTER WITH THE SCORE LINE BETWEEN THEGLUE FLAP PANEL AND THE ADJACENT CORNER PANEL, AND TO TERMINATE AT THEJUNCTION OF SAID LAST NAMED SCORE LINE AND SAID COMMON SCORE LINE, ANEDGE ON THE END FLAP AT THE END OF SAID OTHER OUTER SIDEWALL PANELEXTENDING ANGULARLY OUTWARD AND UPWARD FROM SAID JUNCTION AND HAVING ALENGTH AND BEING AT AN ANGLE TO SAID COMMON HORIZONTAL SCORE LINE SUCHTHAT THE LOWER END OF SAID ANGULARLY EXTENDING EDGE IS SUBSTANTIALLY INREGISTER WITH THE JUNCTION OF SAID COMMON HORIZONTAL SCORE LINE AND THEUPPER END OF THE SCORE LINE BETWEEN THE GLUE FLAP AND ADJACENT FLATCORNER PANEL AND THE OTHER END OF SAID ANGULARLY DISPOSED EDGE ISSUBSTANTIALLY IN REGISTER WITH THE LOWER END OF THE CUT LINE SEPARATINGTHE FOLDABLE END FLAPS AT THE UPPER ENDS OF THE GLUE FLAP PANEL AND THEADJACENT SIDEWALL PANEL, AND A VERTICAL EDGE ON THE SIDE OF THE END FLAPAT THE UPPER END OF SAID OTHER SIDEWALL PANEL EXTENDING UPWARD FROM THEUPPER END OF SAID ANGULARLY DISPOSED EDGE AND ADAPTED TO REGISTERTHROUGH AT LEAST A PORTION OF ITS LENGTH WITH THE EDGE OF THE FOLDABLEFLAP AT THE UPPER END OF SAID GLUE FLAP FORMED BY THE CUT LINE BETWEENSAID LAST NAMED FLAP AND THE ADJACENT FOLDABLE END FLAP, THE ADJACENTSIDEWALL PANELS AND SAID OUTER SIDEWALL PANEL AND GLUE FLAP IN THEREGION BELOW SAID UPPER END PORTION OF THE BLANK BEING CONNECTED ALONGSINGLE FOLD LINES SUBSTANTIALLY IN ALIGNMENT WITH THE VERTICAL CENTERLINES OF THE CORRESPONDING CORNER PANELS, AND THE UPPER ENDS OF SAIDSINGLE FOLD LINES AND THE LOWER ENDS OF THE CORRESPONDING CORNER PANELFOLD LINES DEFINING THE CORNERS OF SMALL TRIANGULAR PANELS AT THE LOWERENDS OF THE CORNER PANELS.